HMG-CoA reductase inhibitors, more commonly known as statins, are a class of drugs used to lower cholesterol levels. They are reported to work by inhibiting the enzyme HMG-CoA reductase, which plays a central role in the production of cholesterol in the liver. Hypercholesterolemia is considered to be one of the major risk factors for atherosclerosis which often leads to cardiovascular, cerebrovascular and peripheral vascular diseases. The statins inhibit cholesterol synthesis in the body and that leads to reduction in blood cholesterol levels, which is thought to reduce the risk of atherosclerosis and diseases caused by it.
The best-selling statin drug is atorvastatin, marketed as LIPITOR and manufactured by Pfizer. A number of other statins are also currently on the market: fluvastatin, lovastatin, pitavastatin, pravastatin, rosuvastatin, and simvastatin.

While atorvastatin has been shown in numerous studies to be an effective cholesterol-lowering and low density lipoprotein uptake reducing drug, it is not without its shortcomings. Among these shortcomings, atorvastatin has low bioavailability after oral administration and a high number of perceived side effects. The absolute bioavailability of atorvastatin is approximately 14% which is thought to be the result of two major factors: atorvastatin undergoes high intestinal clearance and first-pass metabolism and, importantly it is insoluble in aqueous solution. Side effects include, among others, the potential for causing liver and muscle disease. This is the result of increased load requirements secondary to atorvastatin's low systemic availability.